Compound piston for internal-combustion engines



June 18,- 19.29. F A, wlTTENBQRN 1,718,097

COMPOUND PISTON FOR INTERNAL COMBUSTION ENGINES Filed Aug. 18, 1927 2 Sheets-Sheet l mvENToR ATTORN EY 4., f WITNESS: M

June 18, 1929. F. A. WITTENBORN COMPOUND PISTON FOR INTERNAL COMBUSTION ENGINES 2 Sheets-Sheet 2 Filed Aug. 18, 1927 INVENTOR ATTORNEY WITNESS: ((215 Patented June 18,1929.

FREDERICK A. WITTENIBOIRN,` F TRENTON, NEW JERSEY.A

COMPOUND PISTON -EOR `IIWIEIEtlTAI-COMBUSTION' ENGINES.

Application led August 18, 1927.v Serial` No. 218,960.

The present invention relates to an imroved construction of compound piston for Internal combustion engines, and the purpose of the invention is to provide a device Bf this character wherein one piston is operable in another pist-on, so that when an explosion occurs in the cylinder an increase of power` may be distributed on less fuel consumption.

Another purpose is to providea. cylinder piston'of compound construction namely one piston operable in a dominant piston, both pistons being so operatively associated that the dominant piston possesses-a substantially wide area at its end as to permit the dominant piston to receive substantially the full benefit of the force or power to be derived from the explosion of a charge, the expansion of the charge acting on an auxiliary piston, so that through the medium of the connecting rods ated with increased power, particularly so as compared with an engine where a single piston may be employed.

Still another purpose is to provide 1n a compound piston improved means for connecting the connecting rod with the dominant piston, and et not interfere with the arrangement ofY the auxiliary piston, to the extent of preventing it from receiving its full impulse from the explosion of the charge.

A further purpose is to provide a crank shaft in connection with the compound piston whereby the two crank portions for eachv compound piston are ofi-set from each other in order to overcome what is known as a dead center during the-rotation of the crank shaft.

It is to be understood that the particulars herein given are in no way limitative, and that while still keeping within the scope of the and proportions may be made in the construction of the appliance according to circumstances.

The invention comprises further features and combination of parts to be hereinafter set forth, shown in the drawings and claimed.

In the drawings z- I Figure 1 is a view in section of the improved compound piston constructed in ac cordance with the invention, showing a portion of the cylinder wall and the crank shaft, illustrating the compound piston in section, and showingthe dominant and auxiliary pistons at the ends of their firing stroke.

Figure 2 is a cross sectional view on line 2 2 of Figure 1.

with the crank shaft, the shaft will be oper-l invention, any desired modification of details Figure 3 is a cross sectional view on line 3--3 of Figure 1.

.Figure 4 is a sectional view on line 4--4 of Flgure 1.

Figure 5 is la lan view of the compound piston, showing t e increased end area of the dominant piston, so that it will receive the full benefit of the explosion of the charge.

Flgure 6 is a sectional view on line 6-6 of Figure 1 showing the arran ement of the compound crank postions of te crank shaft.

Referring to the drawings, 11 identifies the engine cylinder, 2 the cylinder chamber, in which the compound piston is operatively mounted. This compound piston comprises the dominant piston 3 and the auxiliary pis'- ton 4. The dominant piston has. formed therein an auxiliary cylinder 5, in which the auxiliary piston4 is operative. In order to construct the cylinder 5 the dominant piston 3 has an internal wall or web 6, the upper portion of which is offset as identified at 7 and the offset portion of the Wall 6 has a bearing 8 fora wrist pin 9, to which one end of ay connecting rod 10 is pivotally connected. The wrist pin 9 is tubular and engages in a second bearing 11 in the wall of the dominant piston at a point adjacent the cylin-der surace thereof. The wall 12 of the offset portion 7 of the wall 6 constitutes an abutment for the hollow fulcrum pin. This fulcrum pin is inserted in position at a point adjacent the outer circumference of the dominant piston, and is inserted sufliciently to permitof the arrangement of a split expansion ring 13 in the wall of the bearing 11. In other words the wrist pin 9 is short enough, so that when it is inserted its end is counter sunk from the cylindrical surface of the -dominant piston. This sp1-it ex ansion ring enga es a seat 14 in the wall o the bearing 11 an overlies the end of the fulcrum pin 9 to prevent endwise movement.

The connectin rod 10 has a sleeve 15, in which a bronze gushing 16 is mounted, the bronze bushin 16 operatively engages about the wrist pin The sleeve of the connecting rod 10 has an oil passage 17 which also registers with a similar passage 18 in the Wall of the bushings 16, to enablbe the bushings to be lubricated.

The cylinder 5 of the dominant piston is excentric to the center of the dominant piston, and the auxiliary piston 4 operated in the cylinder 5.

The auxiliary piston 4 is Substantially similar to the general type of pistons with the exception that its wrist pin 18 is held in its bearings 19 by the opposite abutment split expansion rings 20, which are engaged in seats 21 at the remote ends of the bearings 19. Also the Wrist pin 18a is hollow, allowing the lubricant to be distributed on the wall of the cylinder 5.

Operatively connected to the wrist pin 18a by means of a bronze bushings is a connecting rod 23. A sleeve 24 at the end of the connecting rod 23 has an opening 25 which registers with a similar opening 26 in the bronze bushings 22 for the purpose of lubricating the Wrist pin.

The wall of the auxiliary piston has openings 27 to permit lubricant to reach the inner surface of the cylinder 5, and so is the dominant piston provided with similar openings` 28 devised for permitting lubricant to reach the inner surface of the cylinder 2.

The dominant and auxiliary pistons are provided with the usual expansion oil packing rings 29 and 30.

The 'connecting rods 10 and 23 are operatively connected to the crank portions 31 and 32 of the crank shaft 33, and the sleeves 34 and 35 which engage with said crank portions 31 and 32 contain Babbitt bushings 36 and 37.

It is to be noted that due to the offset portions 7 of the Wall 6 and the fact that the fulcrum pin 9 is to one side of the cylinder 5, the dominant piston has a relatively wide end area 38, in order to derive the full benefit of the expansion of the charge. While the auxiliary piston withstands a relatively substantial portion of the explosion, its power is derived more or less through the expansion of the charge, and due to the crank portions 31 and 32 being o'set relative to each other, what is known as a dead center is readily overcome.

The piston chamber 5 terminates a short distance from the end of the dominant piston 3 so as to providean extension 39 to the chamber 5 to permit of substantial expansion of the explosion of the charge.

The invention having been set forth, what is claimed is:

1. A compound cylinder piston, comprising a dominant piston provided interiorly with an excentrically arranged auxiliary pist0n chamber, the upper portion of the auxiliary piston chamber opening at the extreme sideiportion of and through the top of the dominant piston, the cylinder wall of the auxiliary piston chamber merging into an ofiset housing adjacent the top of the dominant piston, said housing having bearings for a Wrist pin and being open at one side and closed at the opposite side by an end abutment Wall, a connecting rod with one end in the housing and passing through the dominant piston adjacent the wall ofthe auxiliary piston chamber, a wrist pin mounted in said bearings and passing through the end of the connecting rod, the end abutment wall limiting the wrist pin in one direction, and removable means in the open end of the housing to prevent movement of the wrist pin in the opposite direction, a piston mounted in the auxiliary piston chamber, a connecting rod operatively connected tok the auxiliary piston, and a crank sha-ft provided with oli'- sct crank portions connected to both connecting rods, whereby the dominant piston may travel slightly in advance of the auxiliary piston, thereby increasing the power of the crank shaft.

2. In a compound cylinder piston, the combination with a piston chamber, of a dominant piston operable in the piston chamber, said dominant piston having an auxiliary piston chamber opening at the extreme side adjacent the top of the dominant piston, said dominant piston having a connecting rod end receiving housing, a connecting rod with its end operatively mounted and connected to and within said housing, an auxiliary piston mounted in the auxiliary piston c amber, the auxiliary piston being open at both sides and provided with bearings, a wrist pin in said bearings, means comprising spring rings operatively engaged in the open sides of the auxiliary piston adjacent the bearings end mounted on said wrist pin, and a crank shaft provided with off-set means of connection with both connecting rods, whereby one piston may move slightly in advance of the other and hence deriving increased power from the explosion of a charge.

3. ln a compound cylinder piston, the combination with a piston chamber, of a dominant piston operable therein, said dominant piston having an auxiliary piston chamber constructed adjacent the extreme side of the dominant piston and being opened at the top of the dominant piston adjacent the extreme side thereof,y an auxiliary piston movable in the auxiliary piston chamber, connecting rods having certain of their ends provided with wrist pin connections with the dominant and auxiliary pistons, said wrist pin connections being diagonally relatively olf-set, whereby unbinding relative movements are imparted to both pistons, one within the other, and one within the cylinder, and a crank shaft provided with operative ofiset connections with both connecting rods, whereby one piston may operate with increased power relative to the other piston.

In testimony whereof he aiixes his signature.

FREDERICK A. WITTENBORN. 

